Application of OFA-based ERAS for video-assisted thoracoscopic surgery in elderly patients with airway stenosis: A case report

Background: Thoracic surgery without general anesthesia can be traced back to the First World War, and thoracic epidural block was used to complete the operation due to a large number of patients with gunshot wounds who needed emergency thoracic surgery. By reducing the intraoperative opioid dose, intraoperative and postoperative opioid-related adverse events such as respiratory depression, nausea and vomiting, delirium, hyperalgesia, and other side effects can be reduced to the benefit of patients. Methods: A 72-year-old male patient was admitted to the hospital with a 5-day history of multifocal pain throughout the body caused by a fall. The injury was not treated at that time, and the pain gradually increased, accompanied by cough with difficulty expelling sputum. Diagnoses: Left lung contusion; traumatic pneumonia; multiple left rib fractures; left fluid pneumothorax; thyroid tumor of unknown nature, possibly malignant. Grade I tracheal stenosis; Sequelae of cerebral infarction. Because of goiter and severe tracheal compression, the patient was not intubated and received deopiated general anesthesia combined with epidural anesthesia to preserve spontaneous breathing. Outcomes: At the end of the video-assisted thoracoscopic exploration, the patient was immediately conscious and returned directly to the ward 6 min later. The patient was able to move freely after surgery and eat normally within 6 h of surgery. The postoperative visual analog scale score was 2 points, and there were no anesthetic complications during the follow-up. Conclusion: The opioid-free anesthesia strategy of tubeless general anesthesia, allowing spontaneous breathing combined with epidural anesthesia in elderly patients with tracheal stenosis undergoing video-assisted thoracoscopic surgery can not only avoid accidents and injuries caused by tracheal intubation and mechanical ventilation, but can also significantly reduce postoperative respiratory complications, optimize postoperative analgesia, and help achieve enhanced recovery after surgery.


Introduction
Tubeless general anesthesia can reduce the incidence of complications such as intubation-related airway injury, residual neuromuscular block, ventilation-induced lung injury, cardiac dysfunction and postoperative nausea.In the 1950s, Buckingham and Vichniewsky reported more than 600 cases of thoracic epidural anesthesia with preserved spontaneous breathing for thoracic surgery. [1]With the later emergence of the double-lumen endotracheal tube, endotracheal intubation general anesthesia quickly became the gold standard for thoracic surgery, and non-endotracheal intubation thoracic anesthesia was gradually forgotten.With the development of modern medical technology and the improvement of medical techniques, especially the emergence of thoracoscopic technology in surgery, as well as the development and progress of anesthesia monitoring, airway management, anesthetic drugs and anesthesia theory, thoracic anesthesia with preserved spontaneous breathing can return to clinical practice in an updated form.At present, a series of related reports have been published by a number of research centers in China and abroad, which believe that tubeless anesthesia is safe and feasible, and helps to achieve rapid recovery after surgery.Perioperative opioids offer a good analgesic effect, but can also lead to nausea and vomiting, respiratory depression, delirium, hyperalgesia, and other side effects, [2][3][4] thereby prolonging hospital stay and delaying recovery.Several retrospective studies have also demonstrated the feasibility and effectiveness of opioid-free anesthesia (OFA) in thoracic surgery, lowering morphine consumption while reducing postoperative pain scores. [5,6]As an adjuvant drug, esketamine has the advantages of maintaining airway tension and hemodynamic stability, which makes it an ideal choice for anesthesia and sedation. [7]]

Case presentation
The patient (male, 72 yrs old, 172 cm, 63 kg, ASA grade III) had a painful left chest injury for 5 days, caused by a fall while walking.The pain was accompanied by dizziness and headache, but he had no chest tightness, shortness of breath, dyspnea, cough or sputum on initial presentation.No treatment was given at the time, but the pain gradually worsened, accompanied by cough with difficulty expelling sputum, so he was admitted to our hospital.He had a past history of "sequelae of cerebral infarction."He denied a history of surgery, anesthesia, or medication.

Physical examination
Body weight: 63 kg T: 37.0°C HR: 78 bpm RR: 20 bpm BP: 135/69 mm Hg, clear consciousness, acute face, slight shortness of breath.The neck was soft, the trachea deviated to the right.A mass with a size of 4.40 × 2.83 cm (Fig. 1) was palpable on the left side of the neck.It was hard, ill-defined, and poorly mobile.
There was local swelling and tenderness on the left side of the chest without bone rubbing.The breath sounds were coarse in both lungs, and moist rales were heard in the left lung.The muscles of the left limb were slightly weakened, but the muscle tension was normal, and the rest was normal.Arozullah score:

Imaging examinations
A 3-dimensional CT of the chest showed left pneumothorax, with the lung compressed by approximately 10%, and multiple rib fractures on the left side, some of which were obsolete.There were aortic and coronary calcium plaques, as well as a left pleural effusion.The left lobe of the thyroid gland was enlarged in volume with uneven density, resulting in tracheal compression.

Preparation before anesthesia.
Preparation before anesthesia: Prepare according to difficult airway guidelines [11] : Inform the patient of a known or suspected difficult airway; Before anesthesia and during the operation, experts from the otolaryngology head and neck surgery department were invited to the surgical bedside to prepare for tracheotomy at all times; Prepare a tracheotomy kit, direct laryngoscope, difficult intubation scope, video laryngoscope, light rod, guide wire, aspirator, sputum suction tube, oropharyngeal and nasopharyngeal airway, as well as other tracheal intubation equipment; Prepare the subglottic airway from a 3 to 6 size endotracheal tube and the supraglottic airway from a 3 to 5 size laryngeal mask.Prepare a difficult intubation emergency rescue vehicle (with all drugs needed for rescue) and defibrillator.If individual techniques encounter difficulties, combination techniques can be used. [11]3.2.Anesthesia administration.When entering the room, the patients indices were BP: 135/69 mm Hg, HR: 56 bpm, RR: 17 bpm, T: 36.5°C, S P O 2 : 97% during air inhalation, oxygen inhalation for mask 5 L/min, warm fan to keep warm.ECG, NIBP, pulse oximeter saturation (SpO 2 ), T, RR, urine output, bispectral index (BIS) and partial pressure of endtidal carbon dioxide (P ET CO 2 ) were monitored.Intravenous access was opened and penehyclidine hydrochloride 0.01 mg/ kg was given intramuscularly, tropisetron 5 mg was given intravenously, dexamethasone 5 mg was given intravenously and dexmedetomidine was administered using a pump at 16 µg/10 min.Epidural catheterization was performed at T7/ T8, and a test dose of 5 mL 2% lidocaine was given.After 5 minutes, 8 mL 2% lidocaine was injected to make the block level reach T3-T12, after which 3 mL 2% lidocaine was added every 45 minutes (2 times in total).At the same time, a slow esketamine (ESK) infusion at a rate of 10 to 15 µg/kg/min was given over 35 minutes from the beginning of the infusion to the beginning of the operation, and the BIS value decreased from was maintained above 95% during mask oxygen inhalation.The patient could respond to the call, move his limbs independently, and breathe deeply.Six minutes after the end of anesthesia, the patient was transferred back to the ward, with continuous monitoring and mask oxygen inhalation.

Physical examination in the ward.
T: 36.3°C,P: 62 bpm, RR: 19 bpm, BP: 128/72 mm Hg, SpO 2 : 97%, visual analogue scale: 2 points, bilateral pupils equal and round, light reflex positive.The breath sounds of both lungs were coarse, and no dry or wet rales were heard.The heart rhythm was consistent, and no pathological murmur was heard in the auscultation area of each valve.The patient was able to move freely after surgery and could eat normally after 6 hours.The postoperative visual analogue scale score was approximately 2 points, and the follow-up was unremarkable.Written informed consent was obtained from the patient's son for the publication of this case report.

Discussion
The difficulties of anesthesia in this case were as follows: The patient was older and had given up the treatment of a thyroid tumor, so it was impossible to relieve or tracheal compression in the short or long term; Although the shortest diameter of the trachea was 0.65 cm according to imaging, there was no guarantee of successful smooth insertion of the corresponding endotracheal tube; Although the imaging evaluation showed that the thyroid tumor did not invade the inner wall of the trachea, it was not possible to determine whether the blood vessels of the compressed inner wall of the trachea were proliferating.If the tracheal tube were to damage the infiltrating vascular tissue, even a short period of massive bleeding would lead to asphyxia, with disastrous consequences; After applying muscle relaxants during general anesthesia induction, the loss of support around the thyroid tumor may aggravate tracheal stenosis, resulting in insufficient oxygen supply or asphyxia; Even if all goes well and the patient is intubated successfully, it would be unclear when the endotracheal tube can be removed after the operation.Moreover, a possible tracheal collapse after removal of the endotracheal tube is also a challenge; The location of the thyroid tumor was very low, so that the narrowest tracheal segment was 3 cm below the cricoid cartilage and 1.5 cm above the jugular notch, at the level of the second thoracic vertebra.Therefore, preoperative tracheotomy is risky and difficult.Opioids are associated with multiple acute side effects, including nausea, pruritus, respiratory depression, and constipation. [12]When inappropriately treated, acute pain transforms into chronic pain, and the opioid epidemic has become a major public health problem, driving up healthcare costs and reducing patient satisfaction. [13]OFA is a multimodal pain control technique that uses non-opioid drugs to provide adequate analgesia during the perioperative period. [14]One study showed that OFAbased on intravenous-inhalation general anesthesia combined with thoracic paravertebral nerve block may improve postoperative recovery in patients undergoing video-assisted thoracoscopic surgery. [15]A randomized controlled study evaluated changes in pain threshold index and found that OFA combined with dexmedetomidine was feasible for intraoperative pain management. [16]Dexmedetomidine has anxiolytic, sedative, analgesic, saliva-reducing and other effects.As an adjuvant, dexmedetomidine can inhibit the side effects of ketamine such as tachycardia and hypertension. [17]Preclinical experiments have shown that intravenous infusion of dexmedetomidine in combination with ketamine reduces hyperactivity of brain neurons and alleviates ketamine-induced psychiatric side effects. [18] large number of studies comparing intubated and nonintubated general anesthesia, especially in Asian countries, have shown that non-intubated thoracoscopic surgery can reduce the incidence of postoperative complications, shorten the length of hospital stay, and reduce perioperative mortality, indicating that non-intubated thoracoscopic surgery is a safe, effective and feasible anesthesia technique for thoracic surgery.[19] The necessary local anesthesia for non-intubation thoracoscopic surgery includes thoracic epidural anesthesia, cervical epidural  paravertebral block, intercostal nerve block, local anesthesia at the incision site, local vagus nerve block, erector spinae plane block, serratus anterior plane block and pectoralis major nerve block.[20] Non-intubated thoracoscopic surgery can increase the incidence of hypercapnia and intraoperative cerebral oxygen saturation, reduce systemic inflammation, promote early postoperative activities, and accelerate the postoperative recovery of patients.[21] This is also demonstrated in the present patient, who was returned to the ward 6 minutes after the end of surgery.Notably, he was able to move freely after surgery and eat normally 6 hours later.Pulse oximetry reflects oxygenation, and a decreases in SpO 2 values can occur long after hypoventilation but is not detected.[22] In this case, P ET CO 2 was monitored during the operation and maintained at about 27 mm Hg.Although this value cannot be the true end-breath carbon dioxide concentration of patients, because P ET CO 2 is timely, the coherence and regularity of its waveform can help anesthesiologist determine the incidence and degree of respiratory depression.Changes in P ET CO 2 seem to precede changes in SpO 2 , and periods of apnea, decreased respiratory rate, and hypoventilation are easily detected by carbon dioxide monitoring.By measuring P ET CO 2 , it can provide critical and timely information on the ventilatory status of patients, giving early warning of hazards.[23][24][25] Compared with opioid anesthesia, the OFA protocol achieved an equally effective intraoperative pain threshold index in thoracoscopic surgery.[16] Substitution of opioids with ESK can reduce the incidence of mild chronic postoperative pain and side effects in patients undergoing thoracoscopic surgery.[26] In a 70 kg patient, 12 to 24 mg/h (5.7-11.5 µg/kg/min) of ESK is effective in relieving remifentanil-induced respiratory depression (mainly by increasing the respiratory rate).[27] In this case, ESK was pumped at a dose of 10 to 15 µg/kg/min, similar to the published dose, and respiratory depression did not occur.ESK has effective anesthetic and analgesic effects, while still allowing spontaneous breathing and airway reflexes.[28] In addition, it can antagonize N-methyl-D-aspartic acid receptors, relax bronchial muscle activity, inhibit histamine-induced bronchial contraction, as well as reduce tracheal and bronchial muscle spasms.[29] ESK is effective and neuroprotective when used for the swallowing reflex, eye blink reflex, cough reflex and vomiting reflex during anesthesia.[7] In this case, the BIS value was monitored during the operation, although it could not completely reflect the depth of anesthesia. A coparison of the BIS values before and after anesthesia can also be used to roughly judge the depth of anesthesia and guide the pump injection rate of ESK.It has been shown that intravenous ketamine administration under general anesthesia affects BIS values in children in a dose-dependent manner.[30] It is important to note that intrathoracic vagus nerve block and topical anesthesia with 3 to 5 mL lidocaine on the surface of the lung must be performed according to the existing protocol for thoracotomy without intubation.[31] To avoid the hering-breuer reflex caused by intraoperative exploration and compression of the lung, the SpO 2 temporarily decreased below 60%.
In conclusion, the patient presented here had stable vital signs, perfect intraoperative analgesia, and rapid postoperative recovery, so that he could be directly returned to the ward after 6 minutes.Although SpO 2 transiently decreased below 60% during thoracoscopic exploration, the OFA strategy may be safe and effective for enhanced recovery after surgery in patients with tracheal stenosis undergoing video-assisted thoracoscopic surgery.

Figure 1 .
Figure 1.The patient's thyroid tumor measured 4.40 cm in the long dimension and 2.83 cm in the short dimension.

Figure 2 .
Figure 2. The short diameter of the patient's normal trachea was 1.58 cm.

Figure 3 .
Figure 3.The short diameter of the patient's tracheal stenosis was 0.65 cm.